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convergence problem for opening BC (entrainment)

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Old   September 7, 2009, 13:23
Default convergence problem for opening BC (entrainment)
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Hello everyone!

I'm having convergence problem using opening BC with static pressure (entrainment) condition. My other BCs are inlet and outlet. My model is two-phase compressible. I've played around the automatic timescale and local timescale but I still have poor convergence. If I use inlet instead of opening-entrainment, my simulation converges. Do you have any suggestion guys? Entrainment BC is more suitable for my model. Thanks a lot!
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Old   September 7, 2009, 21:50
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The entrainment BC is much harder to converge so if you are having problems converging then I would not use it. It might be better to move your boundary further away so you can use the simpler non-entrainment boundaries.
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Old   September 7, 2009, 22:04
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Thanks a lot for the advice Sir Glenn! Do you think entrainment BC is more mesh sensitive than other BC? Thanks.
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Old   September 8, 2009, 07:49
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It probably is. It is certainly harder to converge in general than the normal BCs. That is why if possible I prefer to move the boundaries further away from the region of interest and use simpler BCs instead.
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Old   September 9, 2009, 22:29
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I got it sir. Thank you so much again!
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